Systematic and efficient pseudomode method to simulate open quantum systems under a bosonic environment

Using the pseudomode model to simulate open quantum systems is important in quantum physics. Here we report a systematic and efficient pseudomode model based on dissipative, noninteracting harmonic oscillators, capable of accurately simulating any type of environmental spectrum. The dynamical evolution is reduced to a Lindblad master equation with only one dissipation term. A simple procedure to determine the parameters of the pseudomodes is proposed. We evaluate its accuracy by some spin-boson models under different environmental spectra. Our findings consistently exhibit high accuracy. Finally, we extend this pseudomode method to larger systems with more complicated interactions. Our method may have potential applications in quantum information.